This application claims the priority of German Patent Document 199 56 358.6, filed in Germany, Nov. 24, 1999, the disclosure of which is expressly incorporated by reference herein.
The German Patent Document DE 40 01 140 C1 shows and describes a coolant guide in a cylinder crankcase of a liquid-cooled V engine; the cross section of said crankcase being depicted in sections. The V-space of this V engine exhibits coolant channels for a coolant inflow and a coolant outflow with respect to the cooling jackets provided in the cylinder banks. These channels are molded into the lengthwise direction of the engine and can be closed with a separate cover. Thus, one cylinder bank is assigned the coolant inflow channel and the other cylinder bank is assigned the coolant outflow channel so as to be adjacent one another. Both coolant channels are separated essentially by a solid rib, whose cross section is triangular. Each of the coolant channels is connected directly to the adjacent cooling jacket in the cylinder bank, adjoining it, by means of breakthroughs in the cylinder bank boundaries. Each coolant channel is connected so as to guide coolant to the cooling jacket of the other separated cylinder bank by means of angular channels provided in the rib.
In this known coolant guide in a V engine, the inflowing coolant enters on the inside of the V-space into the cooling jackets of both cylinder banks and continues to flow on the exhaust gas side in the direction of the cylinder heads, from which it is fed to the coolant outflow channel over separate channels in the cylinder banks. Some examples of significant drawbacks are a poor distribution of heat in the cylinder crankcase, on the one hand, and a significant cost in separate channels, on the other hand due to the arrangement of the coolant channels in the cylinder banks which are arranged separately side by side as well as in the triangular ribs.
The invention is based on the problem of providing an improved coolant guide with a significantly simpler construction with improved thermal distribution for a class of internal combustion engine, designed in particular as a V engine.
This problem is solved in preferred embodiments of the present invention by providing a liquid-cooled internal combustion V engine with cylinder banks which tilt toward one another, comprising:
a cylinder crankcase having a crankcase housing and a pair of cylinder banks configured in a V-shape to form a V space therebetween,
a pair of cylinder heads assigned separately to each of the cylinder banks,
external exhaust gas-sided cooling jackets and internal cooling jackets separated by cylinder pipes in each of the cylinder banks,
a coolant inflow line extending between the cylinder banks in the V space and crankcase housing end-sided distribution channels operable to feed coolant to the respective external exhaust gas-sided cooling jackets,
cross throughflow channels formed in the respective cylinder heads operable to guide coolant flow from the respective exhaust gas-sided cooling jackets to the internal coolant jackets which border the V space,
an outflow line which is formed by crankcase housing end-sided cross walls and a separate cover, and
throttle openings in cylinder bank boundaries in a bottom segment of the V space connecting the internal coolant jackets with the outflow line,
wherein the inflow line is a separate line from the outflow line and is arranged imperviously in break-throughs of the cross walls,
wherein the outflow line is connectable to a coolant pump by an outflow connection arranged in the V-space, and
wherein the inflow line is connectable to a coolant pump by an inflow connection arranged in the V-space.
Preferred embodiments of the invention relate to a liquid-cooled internal combustion engine with cylinder banks that tilt toward one another, in particular a V engine comprising a cylinder crankcase and cylinder heads assigned separately to the cylinder banks. The cylinder banks exhibit external and internal cooling jackets, separated by cylinder pipes. A coolant is fed to the external, exhaust gas-sided cooling jackets by an inflow line, which extends between the cylinder banks in the V-space and by distribution channels, arranged on the side of the end of the crankcase housing. Said coolant passes on the exhaust gas side into the respective cylinder head and drains, according to a cross flow, into the V-space adjacent internal cooling jackets of the cylinder banks, from which the coolant passes by way of throttle openings in the cylinder bank boundaries in the bottom portion of the V-space into an outflow line. The outflow line is formed by crankcase housing end-sided cross walls and a separate cover. The longitudinally penetrating and separately designed inflow line is arranged imperviously in break-throughs of the cross walls. Assigned to a coolant pump connection of the inflow line is a connection of the outflow line, arranged geodetically above the inflow line.
The inventive spatial configuration of a first coolant channel and a second coolant channel in the V-space of a liquid-cooled V engine results in an advantageous manner in a cylinder crankcase whose construction is significantly simplified. In addition to an improved heat distribution, simpler ventilation of the coolant chambers is also achieved not only during the filling process but also in operation on account of the fact that the separate channels are also dispensed with.
In certain preferred embodiments of the invention the connection of the inflow line and the connection of the outflow line are essentially centered relative to the longitudinal center plane of the cylinder crankcase. In this manner a uniform pump arrangement and design is achieved for a coolant pump, arranged at an end face of the cylinder crankcase, for engines with varying V angles.
For automatic support of the ventilation of the coolant chambers, the cover closing the outflow line in the longitudinal direction of the engine, rises in the direction of the connection for the coolant pump.
The invention is described with reference to a V engine, which is shown in segments in the drawings.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.